Display screen or portion thereof with a graphical user interface for a machine-readable label



The FIGURE is front view of a display screen or portion thereof with a graphical user interface for a machine-readable label showing the design.

The dotted broken lines illustrate portions of the graphical user interface for a machine-readable label that form no part of the claimed design. The dashed broken lines illustrate a display screen or portion thereof and form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with a graphical user interface for a machine-readable label, as shown and described. 